Methods and systems for mechanically counting stacked substrates using e.g. so-called rotating counting discs (or like mechanical systems) are already known in the art, for instance from European patent application No. EP 0 737 936 A1 in the name of the present Applicant.
So-called “touchless” counting methods and systems have also been developed in an attempt to avoid the use of mechanical counting devices such as the above rotating counting discs. Such methods and systems are already known in the art, for instance from International applications Nos. WO 2004/097732 A1 and WO 2006/016234 A1, both in the name of the instant Applicant. Other methods and systems are further known from International applications Nos. WO 96/22553 A1 and WO 2004/059585 A1.
It has become apparent that the above touchless counting methods and systems are not sufficiently accurate and robust, and that there remains a need for an improved touchless counting methodology and suitable system for implementing the same.